The T&P and Prv is quite often connected together before the tun dish, it shows it like that in the book.
In this case the pipe from the Prv runs uphill, which is not good practice, and there's no visible tun dish, maybe one round the corner.
Not got a problem with the T&P sharing the drop to the tundish with the PRV but I have looked and looked until my eyes are sore, I see no tundish, I do see the T&P + PRV directly connected with no relief opening in sight.
At the bottom I see pressure reducing valve, balanced cold(I think) check valve and PRV piped up to the T&P. I cannot see any tee off.